Equipment for shoring and stabilizing a sagging or settling building foundation is readily commercially available and operates along the following general principles. The equipment is disposed in an excavation adjacent to the foundation to be stabilized. A lifting or supporting bracket forms part of the equipment and extends under the foundation. A power means, such as an hydraulic cylinder, is attached to the equipment and is utilized to drive individual pier-pipes successively into the ground to form an elongate piling reaching to bedrock. In response to the downwardly directed driving force exerted by the power means, an upwardly directed reaction force is exerted on the support bracket and thus the foundation. While driving the piling to bedrock, the upwardly directed reaction force is generally insufficient to raise the foundation. When the piling reaches bedrock, however, the upwardly directed reaction force will be substantially equal to the downwardly directed driving force since the piling cannot be driven more deeply and the power means will be working against the bedrock through the piling. The power means will therefore be acting to raise the equipment, including the support bracket, upward rather than to drive the piling downward. Thus, an upwardly directed force substantially equal to the driving force of the power means will be exerted on the support bracket and consequently also on the foundation. The foundation can be lifted to its desired position by this lifting force as exerted through the bracket and the bracket can then be permanently affixed to the piling by welding or other known means to shore the foundation permanently.
The known equipment is generally designed for outside use, that is, external to the outside walls of a building or other structure. Occasionally, the wall to be stabilized will be leaning inwardly due to pressure exerted upon it by the surrounding soil and shoring from the exterior side may create a danger of the wall collapsing inwardly. This is especially so since the lifting force will almost never be directed completely parallel to the vertical axis of the wall and thus will likely exert at least a small inwardly directed tipping force or torque on the wall.
Additionally, when the foundation or wall being supported is a house basement foundation or wall, for example, shoring from the exterior of the structure will often require an excavation in depth equal to the floor to ceiling height of the basement. It would be easier in many instances to shore the foundation or wall from the inside of the house where the excavation need only begin at the floor of the basement and go to sufficient depth to insert the support bracket beneath the foundation. The lifting and shoring operation can begin with a substantially smaller excavation if the operation begins inside the structure rather than outside of it.
Thus, shoring and stabilizing a wall from the inside of a structure is often preferable to doing so from the outside thereof. Additionally, occasionally interior walls, especially load-bearing walls, are in need of further support. Since the known equipment is designed, built, and constructed generally for stabilizing exterior walls from the outside thereof, such equipment is often not easily moved into the interior of the structure because of its size and weight. The known equipment is also generally intended for use where large excavations are not any particular problem, which is certainly not the case when shoring is done from the inside. Few homeowners appreciate a large-scale excavation in their basement with the attendant dirt being tracked throughout the home.
It would therefore be desirable to have apparatus that was easily portable, lightweight, and able to operate with a minimum excavation.